The percentage of herbicide-resistant species by family, and the percentage of species considered principal weeds by Holm et al. (1991, 1997) for each of these families.

The most notable aspect of these charts is that five weed families, Poaceae, Asteraceae, Brassicaceae, Amaranthaceae, and Chenopodiaceae account for about 70% of all cases of herbicide resistance even though they represent only 50% of the world's principal weeds. It is apparent that the grasses (Poaceae), the crucifers (Brassicaceae), and the pigweeds (Amaranthaceae) are very prone to the development of herbicide resistance compared to other families and their prevalence as weeds in general.